In a survey done by the local Better Buy store, questions were asked of 300 households that actually purchased big-screen televisions.

In a survey done by the local Better Buy store, questions were asked of 300 households that actually purchased big-screen televisions. The table at left indicates the consumer’s responses to whether the television purchased was a plasma screen and whether they also purchased a DVR in the past 12 months.
1a: What is the probability that a randomly selected big-screen television purchase in this sample is a purchase of a plasma-screen television?
1b: What is the probability that a randomly selected household that purchased a big screen television purchased a plasma-screen AND a DVR?
1c: What is the probability that a randomly selected household purchased a DVR, given that the household purchased a plasma-screen television?